Classifications

• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
  • C08G18/6505—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen the low-molecular compounds being compounds of group C08G18/32 or polyamines of C08G18/38
  • C08G18/6511—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen the low-molecular compounds being compounds of group C08G18/32 or polyamines of C08G18/38 compounds of group C08G18/3203
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/088—Removal of water or carbon dioxide from the reaction mixture or reaction components
  • C08G18/0885—Removal of water or carbon dioxide from the reaction mixture or reaction components using additives, e.g. absorbing agents
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/08—Processes
  • C08G18/0895—Manufacture of polymers by continuous processes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G18/00—Polymeric products of isocyanates or isothiocyanates
  • C08G18/06—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen
  • C08G18/28—Polymeric products of isocyanates or isothiocyanates with compounds having active hydrogen characterised by the compounds used containing active hydrogen
  • C08G18/65—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen
  • C08G18/6505—Low-molecular-weight compounds having active hydrogen with high-molecular-weight compounds having active hydrogen the low-molecular compounds being compounds of group C08G18/32 or polyamines of C08G18/38
  • C08G18/6523—Compounds of group C08G18/3225 or C08G18/3271 or polyamines of C08G18/38
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09D—COATING COMPOSITIONS, e.g. PAINTS, VARNISHES OR LACQUERS; FILLING PASTES; CHEMICAL PAINT OR INK REMOVERS; INKS; CORRECTING FLUIDS; WOODSTAINS; PASTES OR SOLIDS FOR COLOURING OR PRINTING; USE OF MATERIALS THEREFOR
  • C09D175/00—Coating compositions based on polyureas or polyurethanes; Coating compositions based on derivatives of such polymers
  • C09D175/04—Polyurethanes
• • C—CHEMISTRY; METALLURGY
  • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
  • C08G—MACROMOLECULAR COMPOUNDS OBTAINED OTHERWISE THAN BY REACTIONS ONLY INVOLVING UNSATURATED CARBON-TO-CARBON BONDS
  • C08G2150/00—Compositions for coatings
  • C08G2150/50—Compositions for coatings applied by spraying at least two streams of reaction components

Definitions

• This invention pertains to two-component solventless spray compositions for producing polyurethane and poly(urea)urethane coatings, the products produced from these compositions, a process for producing such products, and methods for using them.
• Polyurethane coatings are well known and have gained commercial acceptance as protective and decorative coatings for metal, wood, concrete, foam, and plastics in the aircraft, construction, product-finishing, textile and maintenance/architectural coatings markets.
• the basic raw materials used to prepare these coatings generally comprise as essential components (a) an aliphatic or aromatic di-or-polyisocyanate and (b) a ⁇ o-reactant or curative component bearing active hydrogen containing groups, i.e., hydroxyl or amine groups, or latent active hydrogen containing groups, e.g., oxazolidines or ketimines.
• the ⁇ o-reactant is usually a hydroxyl group containing oligomer chosen from the general classes of polyesters, polyethers, alkyd resins and acryli ⁇ s.
• the ⁇ o-rea ⁇ tant ⁇ omponent is generally the vehi ⁇ le for pigment (grinding) and may also ⁇ ontain other additives su ⁇ h as ⁇ atalysts, plasti ⁇ izers, bitumenous extenders, suspending agents, anti-skinning agents, surfa ⁇ tants, and rheologi ⁇ al modifiers.
• Both the iso ⁇ yanate- ⁇ ontaining ⁇ omponent and the a ⁇ tive hydrogen- ⁇ ontaining ⁇ o-rea ⁇ tant usually ⁇ ontain volatile organi ⁇ solvents whose primary fun ⁇ tion is to lower vis ⁇ osity thereby providing a ⁇ onsisten ⁇ y suitable for spray appli ⁇ ation with ⁇ onventional air, airless and ele ⁇ trostati ⁇ spray equipment.
• VOC has prompted ⁇ oating manufa ⁇ turers and end users to evaluate new ⁇ oating te ⁇ hnologies.
• a solventless polyurethane ⁇ oating is one in which substantially all of the constituents remain in the applied coating.
• the first solventless, urethane coatings were the
• ⁇ urative ⁇ omponent comprised of a blend of a ⁇ tive hydrogen ⁇ ontaining ⁇ o-rea ⁇ tants, for example polyether or polyester polyols and lower MW gly ⁇ ol, with fillers and ⁇ atalyst.
• the ⁇ omponents are usually ⁇ ombined at volumetric mix ratios of 1:1 to 4:1.
• non-rea ⁇ tive, non-volatile la ⁇ tone vis ⁇ osity modifier to dissolve vis ⁇ ous or solid prepolymer and ⁇ urative components to redu ⁇ e vis ⁇ osity of the systems so that they may be applied using airless, plural- ⁇ omponent spray equipmen .
• Part A 25 solventless polyurethane ⁇ ompositions whi ⁇ h ⁇ ombine an iso ⁇ yanate terminated prepolymer ⁇ omponent (Part A) with a ⁇ urative component (Part B) .
• the ⁇ urative ⁇ omponent is a blend of highly rea ⁇ tive polyamine with a slower reacting, higher molecular weight (MW) polyol.
• Part B is a blend of highly rea ⁇ tive polyamine with a slower reacting, higher molecular weight (MW) polyol.
• the polyurethane produ ⁇ ed from preferred embodiments of prepolymer-based, prior-art inventions have superior physi ⁇ al properties su ⁇ h as tensile strength, tear strength, and abrasion resistan ⁇ e ⁇ o pared to one-shot, solventless - ⁇ ating systems.
• su ⁇ h prepolymer-based solventless ⁇ oating systems are generally less sensitive to moisture than one-shot solventless systems be ⁇ ause pre-rea ⁇ tion of the iso ⁇ yanate with polyol to form the prepolymer ⁇ omponent results in less rea ⁇ tive iso ⁇ yanate, typi ⁇ ally 3 to 12% by weight.
• Heating, maintaining and applying ⁇ omponents at 160 - 200°F requires additional equipment su ⁇ h as drum heaters to warm vis ⁇ ous materials to a pumpable vis ⁇ osity, ele ⁇ tri ⁇ al indu ⁇ tion heaters to further raise ⁇ omponent temperatures and redu ⁇ e vis ⁇ osity, and the use of heated hoses to maintain temperature until the ⁇ omponents enter the spray gun.
• Prior-art systems have fast gel times, typi ⁇ ally 0.5 to 3 minutes at appli ⁇ ation temperatures of 160 - 200°F, and must be applied with an internal mix, plural- ⁇ omponent spray gun su ⁇ h as the Binks 43-P.
• Internal mix spray guns of this type are ⁇ onne ⁇ ted to three spray hoses; one for ea ⁇ h ⁇ omponent and one for solvent flushing.
• the hoses increase the weight of the spray gun, make the gun awkward to use, and severely restrict the movement of the applicator in confined areas such as manholes or covered hopper cars.
• a solventless, polyurethane ⁇ oating ⁇ omposition is needed which combines the ease of appli ⁇ ation at ambient temperatures and superior physi ⁇ al properties.
• the two ⁇ omponent, solventless spray composition for producing polyurethane and poly(urea)urethane coatings of the present invention includes substantially equal volumes of an isocyanate- ⁇ ontaining ⁇ omponent and a curative component.
• the isocyanate- ⁇ ontaining ⁇ omponent ⁇ omprises a liquid polyiso ⁇ yanate, polyiso ⁇ yanurate or iso ⁇ yanate-terminated prepolymer or quasi-prepolymer.
• the ⁇ urative ⁇ omponent is comprised of from about 0% to about 15% by weight of one or more polyamines
• the polyamines or alkanolamines preferably have an equivalent weight in the range from about 30 to about 200 and are present in an amount suffi ⁇ ient to form a coating whi ⁇ h is substantially ta ⁇ k-free within about 5 minutes to about 60 minutes after being mixed with the isocyanate-containing component.
• the polyamines or alkanolamines make up from about 2% to about 7% by weight of the ⁇ urative ⁇ omponent and are diethyl toluenediamine.
• the ⁇ urative ⁇ omponent ⁇ an also in ⁇ lude one or more ⁇ atalysts to promote the hydroxyl-isocyanate reaction in formation of a polyurethane or poly(urea)urethane.
• the two components Preferably have an isocyanate to active hydrogen equivalent ratio of from about 0.85 to about 1.15.
• the blend preferably has an average equivalent weight of from about 150 to about 500.
• the present invention also encompasses a method wherein the isocyanate- ⁇ ontaining ⁇ omponent and ⁇ urative ⁇ omponent are separately delivered to a manifold, preferably in a volumetri ⁇ ration of 1:1.
• the ⁇ omponents are then mixed with ea ⁇ h other and sprayed through an atomizing nozzle onto a surfa ⁇ e to produ ⁇ e a polyurethane or poly(urea)urethane ⁇ oating.
• the iso ⁇ yanate- ⁇ ontaining ⁇ omponent and the ⁇ urative ⁇ omponent preferably have vis ⁇ osities less than 1000 ⁇ entipoise at these temperatures.
• This invention provides solventless, polyurethane ⁇ oating ⁇ ompositions which combine the ambient temperature ease of applying solventless, one-shot polyurethane coating systems with the lower moisture sensitivity and superior physical properties of the ⁇ oatings produ ⁇ ed from solventless, prepolymer-based polyurethane ⁇ oating ⁇ ompositions.
• the ⁇ oating system of this invention in ⁇ ludes Parts A and B whi ⁇ h are mixed substantially 1:1 -7- by volume.
• Part B (the curative ⁇ omponent) ⁇ omprises essentially a major portion of a blend of high mole ⁇ ular weight polyol or polyamine and low molecular weight glycol, a minor portion of a highly reactive alkanolamine or polyamine, and an additive to adsorb moisture and C0 2 .
• Part B also produces a thixotropi ⁇ mixture approximately 30 seconds after being combined with the Part A (the iso ⁇ yanate- ⁇ ontaining ⁇ omponent) .
• This thixotropi ⁇ mixture ⁇ an be spray- applied to thi ⁇ knesses of from 20-250 mils on verti ⁇ al surfa ⁇ es without sagging even though it is applied at ambient temperature, and it is ta ⁇ k-free in 5-60 minutes.
• the Part A and Part B components are pumped from separate containers into a manifold where they are mixed 1:1 by volume, and then delivered through a single "whip-hose" to a spray nozzle for application to the surface to be coated.
• This invention provides two- ⁇ omponent, solventless polyurethane ⁇ ompositions whi ⁇ h may be ⁇ ombined at substantially 1:1 by volume, and applied with ⁇ ommer ⁇ ially available, plural ⁇ omponent, airless-spray equipment at ambient temperatures.
• the Part A, or iso ⁇ yanate- ⁇ ontaining component includes a liquid polyisocyanate, polyisocyanurate, or iso ⁇ yanate-terminated prepolymer or quasi-prepolymer with a rea ⁇ tive iso ⁇ yanate ⁇ ontent of from about 12-25% by weight.
• Quasi-prepolymers useful in this invention are materials made by rea ⁇ ting a polyurethane forming polyol or polyamine with an ex ⁇ ess of a polyurethane forming aliphatic or aromati ⁇ polyiso ⁇ yanate su ⁇ h as poly- methylene polyphenyl iso ⁇ yanate, 4,4'-diphenylmethane diiso ⁇ yanate (MDI) , and liquid ⁇ arbodiimide or uretonimine modified MDI variants.
• MDI 4,4'-diphenylmethane diiso ⁇ yanate
• the polyol or polyamines used to make the quasi-prepolymer are poly(alkylene ether) glycols, polyester glycols, polycaprola ⁇ tone gly ⁇ ols, poly ⁇ arbonate gly ⁇ ols, ⁇ astor oils, polybutadiene gly ⁇ ols, polyether-thioether-gly ⁇ ols and the like of whi ⁇ h the following are mentioned as non-limiting examples: polytetramethylene ether gly ⁇ ols, MW 650-2900 polypropylene ether gly ⁇ ols, MW 400-4000 ⁇ astor oil and ⁇ astor oil derivatives, MW 300-1000 poly ⁇ aprola ⁇ tone gly ⁇ ols, MW 300-2000 polydiethylene adipate, MW 500-2000 hydroxyl-terminated Bisphenol A polyols, MW 400-1000 poly ⁇ arbonate gly ⁇ ols, MW 500-2500 polybutylene and ethylene/buty
• the se ⁇ ond ⁇ omponent of the present invention is a Part B or ⁇ urative ⁇ omponent whi ⁇ h is preferably ⁇ omprised of:
• the curative component may also contain pigments or dyes, rheological additives, surfa ⁇ tants, UV stabilizers, and fillers su ⁇ h as sili ⁇ a or silica flour, barytes, talc, aluminum trihydrate, cal ⁇ ium ⁇ arbonate and the like. Catalysts whi ⁇ h promote the hydroxyl-isocyanate rea ⁇ tion in formation of a polyurethane are highly desirable ⁇ onstituents of the ⁇ urative ⁇ omponent.
• su ⁇ h materials as dibutyltin dilaurate, stannous o ⁇ toate, lead o ⁇ toate, phenylmer ⁇ uric proprionate, ferric a ⁇ etyla ⁇ etonate and organo-zin ⁇ ⁇ ompounds su ⁇ h as zin ⁇ o ⁇ toate.
• the preferred ⁇ atalyst is the ⁇ omposition Cotin 222 sold by Cosan Chemi ⁇ al Corporation.
• Cotin 222 is an organo-tin carboxylate containing negligible free acid and is described in detail in U.S. Patent No. 3,661,887, which is incorporated herein by reference.
• Coscat 83 a proprietary organo-metalli ⁇ ⁇ omposition based on bismuth and sold by Cosan Chemi ⁇ al Corp., ⁇ an also be used.
• Catalysts are parti ⁇ ularly desirable when the polyurethane ⁇ oatings are applied in the presen ⁇ e of moisture.
• the ⁇ atalyst promotes the hydroxyl-iso ⁇ yanate rea ⁇ tion in favor of the rea ⁇ tion of iso ⁇ yanate with water so that the superior physi ⁇ al properties of the ⁇ oating are maintained.
• Catalysts also a ⁇ t to a ⁇ elerate the ⁇ ure time of the ⁇ oating and allow appli ⁇ ation to verti ⁇ al surfa ⁇ es without sagging.
• the percent by weight of polyamine or alkanolamine used in the curative component can be reduced to zero.
• this does not result in the most preferable coating because the physi ⁇ al properties of the ⁇ oating suffer somewhat when the per ⁇ ent by weight of polyamine or alkanolamine is redu ⁇ ed below two.
• Quadrol (BASF) , methylene dianiline, menthanediamine, isophorone diamine, 1,4-diamino ⁇ y ⁇ lohexane, Lauramin
• the type of polyamine or alkanolamine sele ⁇ ted depends on the isocyanate-containing ⁇ omponent used to form the polyurethane. If the iso ⁇ yanate ⁇ omponent is based on aliphati ⁇ iso ⁇ yanate, a very rea ⁇ tive aliphati ⁇ or cyloaliphati ⁇ polyamine such as 1,6-hexanediamine,
• PACM-20 sold by Dupont isophorone diamine or menthanediamine is used. If the iso ⁇ yanate ⁇ omponent is based on aromati ⁇ diiso ⁇ yanate, aromatic dia ines su ⁇ h as methylenedianiline, and diethyltoluenediamine may be used.
• the specific amount, if any, of polyamine used reacts to form a thixotropic mixture approximately 15 se ⁇ onds to 2 minutes after mixing with the iso ⁇ yanate ⁇ ontaining component, preferably this amount ranges from
• the second preferred constituent of the curative ⁇ omponent is a gly ⁇ ol or polyol having an equivalent weight of from 30 to 200.
• Useful gly ⁇ ols in ⁇ lude ethylene gly ⁇ ol, trimethylolpropane, 1,3-butylene gly ⁇ ol,
• the presen ⁇ e of the gly ⁇ ol in the ⁇ urative ⁇ omponent helps contribute to the low temperature sprayability of the spray composition.
• the third preferred constituent of the curative component is a relatively high molecular weight polyol or polyamine having an equivalent weight of from 300-2000.
• Particularly useful polyols are polytetramethylene ether gly ⁇ ol, poly(ethylene oxide)-terminated polypropylene ether gly ⁇ ols, ⁇ astor oil, polypropylene ether glycols, polyethylene-butylene adipate gly ⁇ ols, polybutadiene gly ⁇ ols, polyetherthioether gly ⁇ ols and oligomeri ⁇ diaminobenzoates su ⁇ h as Polyamine-1000 sold by Polaroid.
• the fourth preferred ⁇ onstituent of the ⁇ urative #- ⁇ omponent is a non-rea ⁇ tive additive whi ⁇ h reduces blistering and blowing or foaming during application of the solventless polyurethane coating system in humid weather or on damp substrates by combining with or adsorbing moisture and/or carbon dioxide.
• Suitable moisture scavenging additives are cal ⁇ ium sulfate, ⁇ al ⁇ ium oxide and syntheti ⁇ zeolite "mole ⁇ ular sieves".
• the amount of moisture s ⁇ avenging additive used is in ⁇ reased a ⁇ ording to the expe ⁇ ted humidity at the point where the coating is to be applied.
• the low molecular weight polyamine, low mole ⁇ ular weight gly ⁇ ol, high mole ⁇ ular weight polyol, and moisture-adsorbing additive are blended with pigment, ⁇ atalyst and other additives in Part B ( ⁇ urative) to an average equivalent weight of from 150 to 500.
• the equivalent weight of the ⁇ urative blend depends on the iso ⁇ yanate ⁇ ontent of the Part A or iso ⁇ yanate ⁇ ontaining ⁇ omponent, and is ⁇ al ⁇ ulated to give an iso ⁇ yanate to a ⁇ tive hydrogen equivalent ratio of from 0.85 to 1.15 based on a 1:1 volumetri ⁇ mixture of Part A to Part B.
• the iso ⁇ yanate and ⁇ urative ⁇ omponents typically have viscosities of less than 1000 centipoise at 70°F and are pumped dire ⁇ tly from drums in two separate 3000 psi,
• 1/4 in ⁇ h ID paint hoses to 1:1 proportioning ⁇ ylinders mounted below a 30:1, air-regulated Gra ⁇ o Bulldog pump whi ⁇ h delivers equal volumes of both ⁇ omponents to a manifold fitted with stati ⁇ mixer.
• the ⁇ omponents are thoroughly mixed as they pass through the manifold and stati ⁇ mixer into a single, 3/16 in ⁇ h ID "whip-hose" and are delivered to a standard, airless spray gun su ⁇ h as a Gra ⁇ o Silver.
• the mixed ⁇ omponents have sufficient potlife to permit the use of 25 to 50 feet of whiphose and "triggering" of the spray gun to the off position for 30-45 seconds.
• the whiphose and standard airless spray gun is less cumbersome than the three hoses and plural- ⁇ omponent, internal-mix spray gun used to spray prepolymer-based polyurethane ⁇ oating systems, and is easier to use in ⁇ onfined or restri ⁇ ted-access areas.
• Triggering of the spray gun off during the ⁇ oating operation often results in less overspray and more e ⁇ onomi ⁇ al use of material as the gun is moved from a sprayed area to a non-sprayed area.
• the mixed ⁇ omposition is atomized at the spray gun tip and deposited on the surface to be coated at thicknesses of from 15 to 30 mils per pass.
• the thixotropic mixture permits multiple passes of the spray gun and ⁇ ontinuous film build up to 250 mils without sagging.
• the applied ⁇ oating is ta ⁇ k-free in from 5 to
• the ⁇ oating ⁇ ompositions of the present invention exhibit ex ⁇ ellent adhesion by themselves to many substrates in ⁇ luding metal, wood and ⁇ oncrete.
• a primer or adhesive is not required for many applications, if the substrate has been properly prepared and cleaned.
• Coating compositions of the present invention exhibit ex ⁇ ellent adhesion to ferrous metal substrates whi ⁇ h have been sandblasted to a near-white metal finish
• Amer ⁇ oat R 460, Amer ⁇ oat R 66, and Amerlo ⁇ k R 400 should be used. Con ⁇ rete with rough surfa ⁇ es or ⁇ ra ⁇ ks may be , filled with a ⁇ ementitious ⁇ oating su ⁇ h as Nu-Klad R 965 or an epoxy-surfa ⁇ er su ⁇ h as Nu-Klad R 114 and then sealed with a primer su ⁇ h as Amerthane R 135.
• polyurethane ⁇ oatings useful in many appli ⁇ ations.
• the iso ⁇ yanate and curative components are selected for a particular application based on the physi ⁇ al ⁇ hara ⁇ teristics and chemical resistance chara ⁇ teristi ⁇ s of the polyurethane they produce.
• coating systems based on polytetramethylene ether glycol are well suited for applications whi ⁇ h require good resistan ⁇ e to abrasive wear su ⁇ h as ore-handling equipment, and hopper ⁇ ars.
• Coating systems based on ⁇ astor oil provide good hydrolyti ⁇ stability and ⁇ he i ⁇ al resistan ⁇ e, su ⁇ h as for wastewater treatment 15 ponds and ⁇ hemi ⁇ al or ⁇ rude oil storage tanks.
• the spray system of this invention has major advantages ⁇ ompared to high-solids, solvent- ⁇ ontaining
• polyurethane ⁇ oating systems • polyurethane ⁇ oating systems; solventless, one shot polyurethane ⁇ oating systems; and prior-art solventless, prepolymer-based polyurethane ⁇ oating systems.
• the spray system of the present invention can, with multiple passes, apply high coating thi ⁇ knesses of from 20 to 250 mils without sagging ⁇ ompared to 10 to 40 mils for solvent- ⁇ ontaining systems.
• Tack-free time and curing are short, which allows for quick re ⁇ oating and redu ⁇ es the time required for the applied ⁇ oating to be handled or pla ⁇ ed in servi ⁇ e. 35 -15- 4.
• the solventless system of the present invention requires less volume to apply the same dry film thickness than a solvent-containing system; there is less material to store, handle, and apply. 5. Problems associated with solvent-containing systems such as shrinkage, blistering, holidays and premature deadhesion ⁇ aused by solvent retained in the applied coating are signifi ⁇ antly redu ⁇ ed.
• the major advantages of the present invention compared to solventless, one-shot, polyurethane coating systems are reduced sensitivity to moisture-generated foaming, and improved physical properties such as higher tensile and tear strength.
• Spray compositions of the present invention have equivalent physical properties such as tensile and tear strength compared to prior-art, solventless, prepolymer-based polyurethane systems but have the following major advantages:
• Spray compositions of the present invention are low viscosity liquids that can be applied at 70°F - 100°F. The need for expensive, additional equipment required to preheat, maintain and apply prepolymer-based coating systems is eliminated.
• Coating systems of the present invention are applied with a single paint hose and standard, airless spray gun, which is easier to use than the internal-mix, plural-component guns used to apply prior-art, prepolymer-based coating systems.
• compositions of the present invention have sufficient pot-life to allow triggering of the spray gun for 30-45 seconds, which reduces overspray and consumes less material when coating compli ⁇ ated shapes.
• the ⁇ omponents of the present invention are ⁇ ombined
• whi ⁇ h is desirable for optimum , mixing, and is more forgiving to off-ratio ⁇ onditions whi ⁇ h frequently o ⁇ ur during field appli ⁇ ation using plural ⁇ omponent, airless spray equipment.
• the ingredients were heated at 100°C under va ⁇ uum until the moisture content was less than 0.08% by weight.
• Example I was used with the ⁇ omponents listed below.

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• 1986
  • 1986-05-23 US US06/867,337 patent/US4695618A/en not_active Expired - Fee Related
• 1987
  • 1987-05-26 WO PCT/US1987/001216 patent/WO1987007287A1/en not_active Application Discontinuation
  • 1987-05-26 JP JP62504384A patent/JPS63503467A/ja active Pending
  • 1987-05-26 EP EP19870904747 patent/EP0270665A4/de not_active Withdrawn

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